Cooling device and cooling method

ABSTRACT

A cooling device for cooling an object to be processed to a target temperature comprises a plurality of contact members mounted on a placing table, for supporting the object such that the object opposes a top surface of the placing table with an interval, temperature sensors for outputting temperature information of the object supported by the contact members, a first cooling unit for cooling the placing table to a temperature lower than the target temperature to cool the object, a second cooling unit for heating the object cooled by the first cooling unit to a temperature almost equal to the target temperature, and a contrast circuit for performing a switching operation between cooling by the first cooling unit and heating by the second cooling unit on the basis of the temperature information from the temperature sensors.

This application is a Division of application Ser. No. 09/358,459 filedon Jul. 22, 1999, now U.S. Pat. No. 6,216,425 now allowed, which is adivisional of application Ser. No. 08/588,309 filed Jan. 18, 1996, nowissued as U.S. Pat. No. 5,941,083.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and device for cooling anobject to be processed to a target temperature.

2. Description of the Related Art

In general, in the processing steps for, e.g., a semiconductorsubstrate, a glass substrate, or the like, a series of processes inwhich a circuit pattern or the like is reduced and transferred to aphotoresist on the substrate by using a photolithography technique, andthe resultant photoresist is developed are performed. In such processes,the substrate is washed and then heated to completely remove moisturefrom the substrate surface. After the heating, the heated substrate isquickly cooled to an atmospheric temperature to shorten themanufacturing time. As a cooling device for this purpose, a devicedisclosed in Japanese Examined Utility Model Publication No. 6-2262 isknown.

In conventional cooling device, as indicated by a curve a in FIG. 12,even if control is performed using a coolant kept at a targettemperature to cool the substrate having a high temperature K1 to atarget temperature K2, a considerably long time (T3) isdisadvantageously required to cool the substrate to the targettemperature after the temperature of the substrate is close to thetarget temperature K2. In FIG. 12, the ordinate indicates thetemperature (° C.) of the substrate, and the abscissa indicates a time(second). In an example, the temperature K1 is about 130° C., thetemperature K2 is about 23° C., and the time T3 is about 60 seconds.

In addition, in the photolithography step described above, the coolingstep must be performed for one substrate several times. For this reason,in order to increase a throughput, one important problem is to shorten atime for the cooling process.

SUMMARY OF THE INVENTION

It is an object of the present invention, there is provided a processingmethod and a processing device capable of shortening a time required tocool an object to be processed to a target temperature when thetemperature of the object is to be set a predetermined temperature.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed out in theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate presently preferred embodiments ofthe invention and, together with the general description given above andthe detailed description of the preferred embodiments given below, serveto explain the principles of the invention.

FIG. 1 is a perspective view showing the overall arrangement of acoating/developing apparatus including a cooling device according to oneembodiment of the present invention;

FIG. 2 is a schematic view showing the embodiment of the cooling devicein FIG. 1;

FIG. 3 is a plan view showing a placing table of the cooling device inFIG. 1;

FIG. 4 is a partially enlarged sectional view showing the placing tableof the cooling device in FIG. 1;

FIG. 5 is a view for explaining a first coolant supply means constitutedby using a freezer and a heat exchanger;

FIG. 6 is a view for explaining a second coolant supply meansconstituted by using a freezer;

FIG. 7 is a sectional view showing a part of a placing table which isthe same as that in FIG. 4 except that a contact member is not arranged;

FIG. 8 is a flow chart for explaining of the operation of the coolingdevice in FIG. 1;

FIG. 9 is a flow chart using loading of a glass substrate as trigger;

FIG. 10 is a flow chart using loading of a glass substrate by a conveymeans as trigger;

FIG. 11 is a flow chart using descending of a delivering means;

FIG. 12 is a graph showing the operations of processes in the conventiondevice and the embodiment of the present invention;

FIG. 13 is a view for explaining a device according to anotherembodiment of the present invention; and

FIG. 14 is a flow chart for explaining of the operation of the deviceshown in FIG. 13.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

One preferred embodiment of the present invention will be describedbelow such that the present invention is applied to a cooling deviceused in a resist coating/developing apparatus.

The overall arrangement of a coating/developing apparatus comprising acooling device according to an embodiment of the present invention willbe described below with reference to FIG. 1. Referring to FIG. 1,reference numeral 5 denotes a carrier stage, on which carriers 6 eachconstituted to store a plurality of LCD glass substrates and serving asa storing vessel can be placed, for loading or unloading the carrier 6into/from the device. Reference numeral 7 denotes a convey mechanism forloading or unloading a glass substrate into/from the carrier 6.Reference numerals 8 and 9 denote main arms serving as convey means forconveying the substrate to process stations; and 10, a repeater forexchanging the glass substrate between the process stations. The glasssubstrate G in the carrier 6 is conveyed into a washing device 11through the convey mechanism 7 and the main arm 8, and then the glasssubstrate G is water-washed with a brush in the device 11, and the glasssubstrate G is jet-water-washed by a jet water-washing device 12 asneeded. Thereafter, the glass substrate G is dried by a heat-processingunit 13, is conveyed into a first cooling device 14 arranged on thelower stage side of the heat-processing unit 13, and is cooled to apredetermined temperature, e.g., an atmospheric temperature. An adhesionprocessing unit 15 performs a hydrophobic process to the glasssubstrate, and the glass substrate is cooled to a predeterminedtemperature by a second cooling device 16 arranged on the lower stage ofthe adhesion processing unit 15, and a coating device 17 rotationallycoats and forms a photoresist film, i.e., a photosensitive film, on theglass substrate. The photoresist film is heated by the heat-processingunit 13 to perform a pre-baking process to the photoresist film, and apredetermined pattern is exposed by an exposure device (not shown)arranged on the right side of this device. The exposed glass substrateis conveyed into a develop processing unit, developed by a developingliquid, and then returned into the carrier 6 through the main arms 8 and9 and the convey mechanism 7.

The construction of the first and second cooling devices 14 and 16described above will be described below with reference to FIG. 2. Sincethe first cooling device 14 basically has the same structure as that ofthe second cooling device 16, the cooling device 14 is representativelydescribed.

The cooling device 14 comprises a placing table 21 serving as a coolingmeans, on which a glass substrate G is placed, for cooling it. Theplacing table 21 consists of a material, e.g., a metal such as aluminum,having good conductivity to rapidly exchange heat between the placingtable 21 and a coolant. Three or more through holes 22 which verticallyextend are formed in the placing table 21, and a support pin 23 whichcan be vertically moved in the through hole 22 is arranged in eachthrough hole 22. The support pins 23 are vertically moved by a drivemeans including a vertically moving plate 24 which commonly supports thesupport pins 23 and an air cylinder 25 having a drive rod which isconnected to the vertically moving plate 24. When a compressed air issupplied from a compressed air supply means (not shown) into the aircylinder 25, the drive rod is moved upward, and the support pins aremoved upward accordingly through the vertically moving plate 24, and theupper portions of the support pins extend from the upper surface of theplacing table 21. In this state, the glass substrate G held by the mainarm 8 (9) described above is conveyed into the cooling device 14, andthe glass substrate G is delivered onto the upper end faces of thesupport pins 23 above the placing surface of the table. Thereafter, whenthe air in the air cylinder 25 is exhausted, the drive rod is moveddownward, and the upper ends of the support pins 23 are moved downwardfrom the upper surface of the placing table. Therefore, the glasssubstrate G is delivered from the support pins 23 onto the placingsurface (upper surface of contact members (to be described) later whenthe contact members are arranged).

As shown in FIG. 3, four pairs of guide or positioning pins 27 forlocating, at a predetermined position, the glass substrate G placed onthe placing table 21 according to the size of the glass substrate G. Theguide pins 27 are detachably fixed to the upper surface of the placingtable 21 by selectively inserting the lower end portions of the guidepins 27 into vertical insertion bores (not shown) formed in the uppersurface of the placing table 21. Therefore, even if the glass substrateG is changed in size, positioning of the glass substrate G changed insize can be performed by inserting the guide pins 27 into insertionbores corresponding to the size of the glass substrate G.

As shown in FIGS. 3 and 4, the glass substrate G is kept slightlyfloating from the upper surface of the placing table 21 and opposing theupper surface of the placing table 21 to prevent dust on the uppersurface of the placing table 21 from adhering to the glass substrate G,and the placing table 21 has a plurality of contact members 26 arrangedon the upper surface of the placing table 21 to suppress accumulationcharging of the glass substrate G. Since the glass substrate G isdirectly placed on the upper surface of the contact members 26, theupper surface of the contact members 26 is defined as a placing surfacein this embodiment. The contact members and placing table constitute asupport means for supporting an object to be processed. The contactmembers 26 can preferably consist of a good conductive material, e.g., ametal such as aluminum, for making the conductivity of heat from theplacing table 21 better. The contact members 26 may be formed by memberswhich are as thin (low) as possible, e.g., 0.1 mm or less to rapidlyperform thermal conducting in the gap between the upper surface of theplacing table 21 and the low surface of the glass substrate G by heatradiation and heat conversion. As such thin contact members, forexample, polyimide film pieces which are electrical insulators but canbe easily shaped. In order to give the heat conducting effect and chargesuppression effect to the insulating contact member, a conductive filmsuch as aluminum film may be coated on the surface of the insulatingcontact member.

Inside the placing table 21, as shown in FIG. 2, a coolant circulatingpath for circulating a coolant such as cooling water, e.g., a coolantpath 28 serving as a cooling unit and the upper portions of a pair offirst pipes 29 is arranged. The coolant path 28 is arranged near theupper surface of the placing table 21, as shown in FIG. 3, and thecoolant path 28 horizontally extends to wind from one end side to theother end side. The coolant path 28 is not limited to such a shape, butcan have various shapes. For example, the coolant path 28 is formed as arectangular chamber corresponding to the glass substrate. The pipes 29are connected to both the ends (inlet and outlet) of the coolant path28, vertically passes through the placing table 21, and extend from thelower surface of the placing table 21 to outside. Both the ends of asecond pipe 29 a and a third pipe 29 b are commonly connected to theother end of the first pipe 29. The second pipe 29 a has a first coolantsupply means 30 for causing a first coolant, e.g., cooling water, toflow into the second pipe 29 a, and the third pipe 29 b has a secondcoolant supply means 31 for causing a second coolant, e.g., coolingwater, to flow into the third pipe 29 b. As a result, the first supplymeans 30, the first pipes 29, and the second pipe 29 a constitute afirst coolant supply unit for supplying the first coolant into thecoolant path 28 to circulate the first coolant. The second supply means31, the first pipes 29, and the third pipe 29 b constitute a secondcoolant supply unit for supplying the second coolant into the coolantpath 28. A pair of first electromagnetic valves 32 and 33 are arrangedat the portions of the second pipe 29 as near the connection portionbetween the second pipe 29 a and the first pipes 29, and a pair ofsecond electromagnetic valves 34 and 35 are arranged at the portions ofthe third pipe 29 bs near the connection portion between the third pipe29 b and the first pipes 29. The four electromagnetic valves areconnected to a control means (CPU) 37 and opened/closed on the basis ofa command from this control means, thereby making it possible toselectively supply the first and second coolants into the coolant path28. More specifically, when, according to a command from the controlmeans 37, the first electromagnetic valves 32 and 33 are opened, and thesecond electromagnetic valves 34 and 35 are closed, the first coolant issupplied from the first supply unit into the coolant path 28. Incontrast to this, when the first electromagnetic valves 32 and 33 areclosed, and the second electromagnetic valves 34 and 35 are opened, thesecond coolant is supplied from the second supply unit into the coolantpath 28.

The first coolant supply means 30 supplies a coolant having atemperature lower than a temperature at which the glass substrate G iscooled, i.e., a target temperature (K2 in FIG. 12), into the coolantpath 28. As a coolant used in the first coolant supply means 30, forexample, water cooled to a temperature of, e.g., about 18° C., citywater, or other liquid can be selected. In place of the above coolingmethod, the following method can be used. That is, a coolant consistingof a gas such as a fleon gas is supplied into the coolant path 28 tooperate the placing table 21 as an evaporator, thereby performingcooling using latent heat.

As shown in FIG. 5, for example, the first coolant supply means 30 canbe constituted by a freezer 50 and a heat exchanger 51. In this device,both the ends of the second pipe 29 a are connected to each other by aprimary coil 52 of the heat exchanger 51. A secondary coil 53 of theheat exchanger is connected to the freezer 50 to supply alow-temperature coolant formed by the freezer. As a result, in the heatexchanger, the coolant flowing in the primary coil 52 is cooled to thetarget temperature K2 or less by the low-temperature coolant flowing inthe secondary coil 53, and the cooled coolant is caused to flow into thecoolant path 28 through the first electromagnetic valves 32 and 33. Thecoolant warmed by the glass substrate, in the coolant path 28 is cooledin the primary coil 52 and supplied into the cooling path again. Inorder to prevent the first coolant flowing in the primary coil 52 of theheat exchanger 51 from being excessively cooled, an auxiliary heater 54is arranged in the heat exchanger. The auxiliary heater 54 receives atemperature information signal from a temperature detection means (to bedescribed later), and can be controlled by the control means 37. Inplace of this method, the freezer 50 may be ON/OFF-controlled by thecontrol means 37, or both of the auxiliary heater 54 and the freezer 50may be controlled by the control means 37.

In place of the above arrangement, for example, as shown in FIG. 6, thefirst coolant supply means 30 may be constituted by only a freezer 60.In this example, as shown in FIG. 6, a cavity having a relatively largecapacity is formed in the placing table 21, and the overall cavity rulesthe coolant path 28. An auxiliary heater 61 is arranged in the coolantpath 28 to prevent the placing table 21 from being excessively cooled.This heater 61 (including the freezer 60 as needed) can be controlled bythe control means 37 as in the example shown in FIG. 5. According to theexample shown in FIG. 6, the first coolant can be cooled to a lowtemperature, and the glass substrate can be cooled at a high speed. Inaddition, spontaneous conversion of the first coolant occurs in thecoolant path 28 to make thermal diffusion uniform, and not only theplacing table 21 but also the glass substrate can be entirely, uniformlycooled.

As described above, the various arrangements may be employed as thearrangement of the first coolant supply means 3. However, if the coolingdevice is arranged in a high-humidity atmosphere, when a coolant havingan extremely low temperature is supplied from the first coolant supplymeans 30 into the placing table 21, dew condensation may occurs on theouter surface of the placing table 21 or the outer peripheral surface ofthe pipes 29. When such dew condensation occurs, accurate temperaturecontrol cannot be easily performed due to the heat of evaporation of thedew condensation. For this reason, in this environment a coolant havinga low temperature at which the view condensation does not occur, e.g.,about 18° C., is preferably supplied from the first coolant supply means30 into the coolant path 28.

The second coolant supply means 31 is set to supply a coolant having atemperature almost equal to the target temperature at which the glasssubstrate G is cooled in to the coolant path 28. More specifically, whenthe target temperature for cooling the glass substrate is about 23° C.,the second coolant supply means 31 supplies and circulates a coolanthaving a temperature of about 23° C., e.g., constant-temperature waterhaving a temperature of 23° C., into the coolant path 28 through asecond supply path.

As shown in FIG. 2, a temperature detection means such as a temperaturesensor, e.g., a thermo couple 36 is arranged at least one portion in theplacing table 21, near the surface on which the substrate is placed. Thetemperature sensors 36 are preferably arranged at the central andperipheral portions on (in) at least the upper surface of the substrateto accurately measure a temperature distribution in the plane of thesubstrate. Temperature informations detected by these temperaturesensors 36 are transmitted to the control means 37 as an electricalsignals not only to open/close the first and second electromagneticvalves 32 to 35 to control the auxiliary heater 54 (61) and the freezer50 (60) as needed. When a plurality of temperature sensors are used, forexample, an average temperature can be used as temperature information.

Since the basic arrangement of the second cooling device 16 issubstantially the same as that of the first cooling device 14 shown inFIG. 2 except for the point described below, a detailed description ofthe second cooling device 16 will be omitted. In this cooling device 16,as shown in FIG. 7, unlike the first cooling device 14, the contactmembers 26 are not arranged, the upper surface of the placing table 21is used as a placing surface, and the glass substrate G is directlyplaced on the upper surface of the placing table 21. As a result, thecooling device 16 can cool the glass substrate G as a whole withoutununiformity.

The operation of the above processing device will be described belowwith reference to the flow charts shown in FIGS. 8 to 11.

In the processing device in FIG. 1, the glass substrate G is held by themain arm 8 from the carrier 6, conveyed into the washing device 11,water-washed with a brush, and jet-water-washed by a jet water-washingdevice 12 as needed. Thereafter, the glass substrate G is conveyed intothe heat-processing unit 13. After the glass substrate G which isheat-processed at a temperature of about 90° C. or more in theheat-processing unit 13 is unloaded from the heat-processing unit 1 bythe main arm 9, the glass substrate G is conveyed into the coolingdevice 14 and then delivered by pre-programmed procedures onto the upperends of the support pins 23 which extend from the upper surface of theplacing table 21 and are on standby. Thereafter, the main arm 9 iswithdrawn from the cooling device 14.

In the cooling device 14, the following processes are performedaccording to the flow charts shown in FIGS. 8 to 11. The processingsteps shown in FIG. 8 will be described below. The operation of the aircylinder 25 is started. In step S10, the support pins 23 having uppersurfaces which support the glass substrate G are moved downward, and theglass substrate G is placed on the placing surface of the placing table21. At this time, the temperature of the placing table 21 is kept at thetarget temperature; K2, e.g., atmospheric temperature, e.g., 23° C.

In step S11, the temperature sensors 36 intermittently or continuouslydetect the temperature near the upper surface of the placing table 21.In step S12, the control means 37 checks, on the basis of the detectedtemperature detection signal, whether the temperature of the placingsurface is changed by placing the substrate G on the placing surface. IfNO in step S12, the control means 37 determines that the temperature ofthe glass substrate G is atmospheric temperature to stop the coolingprocess, and the control means 37 restarts driving of the air cylinderto move the support pins 23 upward, in order to convey the glasssubstrate G to the next processing step. On the other hand, when anascending temperature near the upper surface of the placing table 21 isdetected by the temperature sensors 36, a cooling process is started instep S13. More specifically, the second electromagnetic valves 34 and 35are closed by a control signal from the control means 37 which receivesthe temperature detection signal, and then, or at the same time, thefirst electromagnetic valves 32 and 33 are opened. The first coolanthaving a temperature (e.g., 18° C.) which is lower than the targettemperature (e.g., 23° C.) and at which dew condensation does not occur,is supplied and circulated into the coolant path 28 in the placing table21 through the first supply path. As a result, the glass substrate G isquickly cooled. This cooling is continued while the temperature near theupper surface of the placing table 21 is detected by the temperaturesensors 36. When the control means 37 determines, on the basis of thetemperature detection signal, that the temperature of the glasssubstrate G becomes the target temperature or less (step S15), thecontrol means 37, at the same time or a predetermined time after,transmits a control signal to the switching means or valves 32 to 35,and, at the same time or after the second coolant having the targettemperature (e.g., 23° C.) is supplied, stops the supply of the firstcoolant (step S16). More specifically, the first electromagnetic valves32 and 33 are closed, and the second electromagnetic valves 34 and 35are opened. When the first coolant is switched to the second coolant,the temperature of the glass substrate G can be quickly controlled to bethe target temperature while the temperature is detected by thetemperature sensors 36 (step S17). When the control means 37 detectsthat the temperature reaches the target temperature through thetemperature sensors 36 (step S16), driving of the air cylinder 25 isrestarted to move the glass substrate G upward from the placing surfaceof the placing table 21. The glass substrate G is unloaded from thecooling device 14 by the main arm 9 serving as a convey means, and theflow is shifted to, e.g., an adhesion processing step (to be describedlater).

The processing step shown in FIG. 9 will be described below. Before theglass substrate G is placed on the placing table 21, in step S20, acoolant having a predetermined temperature, e.g., 23° C. is suppliedfrom the second coolant supply means 31 into the coolant path 28 of theplacing table 21 in advance by opening the second electromagnetic valves34 and 35 to set the temperature of the placing table 21 at apredetermined temperature. In step S21, the support pins 23 are moveddownward to place the glass substrate G on the placing table 21. In stepS22, the temperature sensors 36 detect a temperature near the uppersurface of the placing table 21, and in step S23, the control means 37checks whether the temperature of the placing surface changes. If NO instep S23, a cooling process is stopped, the glass substrate G isconveyed to the next processing step. On the other hand, when thetemperature ascends in step S24, the second electromagnetic valves 34and 35 are closed, and the first electromagnetic valves 32 and 33 areopened to supply a first coolant having a temperature lower than apredetermined temperature, e.g., 18° C., from the first coolant supplymeans 30 into the coolant path 28. In step S24, as a timing at which thesupply of the coolants is switched, for example, the coolant supply maybe switched simultaneously with a change in temperature of the placingtable 21 by placing the glass substrate G on the placing table 21,otherwise, the coolant supply may be switched a predetermined time afterthe change in temperature of the placing table 21 is detected.

According to the processing steps shown in FIG. 9, a change intemperature of the placing table 21 is used as a trigger, the firstcoolant is supplied into the coolant path 28 the moment of thetemperature changes or a predetermined time after the temperaturechanges, thereby making it possible to quickly cool the glass substrateG. When the temperature of the glass substrate G becomes lower than apredetermined temperature, e.g., 23° C., in step S26, the secondelectromagnetic valves 34 and 35 are opened and the firstelectromagnetic valves 32 and 33 are closed in step S27 to supply acoolant having a predetermined temperature, e.g., 23° C., from thesecond coolant supply means 31 into the coolant path 28. When it isdetected in step S29 that the temperature of the glass substrate Gbecomes the predetermined temperature, it is determined that the coolingprocess is finished. In this manner, the glass substrate G cooled to thepredetermined temperature is unloaded from the cooling device 14 by themain arm 9 serving as the convey means, and the flow is shifted to,e.g., an adhesion processing step (to be described later).

The processing steps shown in FIG. 10 will be described below. In theprocessing steps, as in the processing steps shown in FIG. 9, before theglass substrate G is placed on the placing table 2, in step S30, acoolant having a predetermined temperature, e.g., 23° C. is suppliedfrom the second coolant supply means 31 into the coolant path 28 of theplacing table 21 in advance to set the temperature of the placing table21 at a predetermined temperature. In step S31, the glass substrate G isloaded onto the placing table 21 by the main arm serving as a conveymeans and delivered to the support pins 21. Thereafter, the support pins23 are moved downward to place the glass substrate G on the placingtable 21. In step S31 or before or after step S31, the secondelectromagnetic valves 34 and 35 are closed and the firstelectromagnetic valves 32 and 33 are opened in step S32 to supply acoolant having a temperature lower than a predetermined temperature,e.g., 18° C. from the first coolant supply means 30 into the coolantpath 28. In step S32, as a timing at which the supply of the coolant isswitched, for example, the coolant supply may be switched the moment aproper sensor (not shown) detects that the glass substrate G is loadedonto the placing table 21, otherwise, the coolant supply may be switcheda predetermined time after the sensor detects that the glass substrate Gis loaded onto the placing table 21. In addition, for example, thecoolant supply may be switched the moment a command for loading theglass substrate G into the cooling device 14 is output to the main arm9, otherwise, the coolant supply may be switched a predetermined timeafter the command for loading the glass substrate G into the coolingdevice 14 is output.

According to the processing steps shown in FIG. 10, when the firstcoolant is supplied into the coolant path 28 at a predetermined timingby using loading of the glass substrate G as a trigger, the glasssubstrate G placed on the placing table 21 can be quickly cooled. Whenthe temperature of the glass substrate G becomes lower than apredetermined temperature, e.g., 23° C., in step S34, the secondelectromagnetic valves 34 and 35 are opened and the firstelectromagnetic valves 32 and 33 are closed in step S35 to supply thesecond coolant having a predetermined temperature, e.g., 23° C., fromthe second coolant supply means 31 into the coolant path 28. Thetemperature of the placing table 21 is detected (step S36). When it isdetermined that the temperature of the glass substrate G becomes thepredetermined temperature (23° C.), the cooling process is finished. Inthis manner, the glass substrate G cooled to the predeterminedtemperature is unleaded from the cooling device 14 by the main arm 9serving as the convey means, and the flow is shifted to, e.g., anadhesion processing step (to be described later).

The processing steps shown in FIG. 11 will be described below. In thisstep, as in the processing steps shown in FIGS. 9 and 10, before theglass substrate G is placed on the placing table 21, in step S40, acoolant having a predetermined temperature, e.g., 23° C. is suppliedfrom the second coolant supply means 31 into the coolant path 28 of theplacing table 21 in advance to set the temperature of the placing table21 at a predetermined temperature. In step S41, the glass substrate Gwhich is delivered by the main arm 9 serving as a convey means is placedon the placing table 21 by moving the support pins 23 downward. In stepS41 or after step S41, the second electromagnetic valves 34 and 35 areclosed and the first electromagnetic valves 32 and 33 are opened in stepS42 to supply a coolant having a temperature lower than a predeterminedtemperature, e.g., 18° C. from the first coolant supply means 30 intothe coolant path 28. In step S42, as a timing at which the supply of thecoolant is switched, for example, the coolant supply may be switched byusing, as a trigger, a command for starting the downward movement of thesupport pins 23, otherwise, the coolant supply may be switched apredetermined time after the command for starting the downward movement.In addition, when downward movement of the support pins 23 or the glasssubstrate G is detected by using, e.g., a proper sensor (not shown), thecoolant supply may be switched by using the detection as a trigger.

In this manner, according to the processing steps shown in FIG. 11, whenthe first coolant is supplied into the coolant path 28 at apredetermined timing by using the downward movement of the support pins23 as a trigger, the glass substrate G placed on the placing table 21can be quickly cooled. In step S44, when the temperature of the glasssubstrate G becomes lower than a predetermined temperature, e.g., 23°C., the second electromagnetic valves 34 and 35 are opened and the firstelectromagnetic valves 32 and 33 are closed in step S45 to supply acoolant having a predetermined temperature, e.g., 23° C., from thesecond coolant supply means 31 into the coolant path 28 of the placingtable 21. When it is determined in steps S46 and S47 that thetemperature of the glass substrate G becomes a predeterminedtemperature, it is determined that the cooling process is finished, theglass substrate G cooled to the predetermined temperature is unloadedfrom the cooling device 14 by the main arm 9 serving as the conveymeans, and the flow is shifted to, e.g., an adhesion processing step (tobe described later).

In this manner, one of a series of processing steps of photolithography,e.g., an adhesion process is performed to the glass substrate G which iscooled to the predetermined temperature according to any step of thesteps shown in FIGS. 8 to 11 described above and which is unloaded fromthe cooling device 14 by the main arm 9 serving as a convey means. Theglass substrate G is conveyed into the adhesion processing unit 15 bythe main arm 8, and a hydrophobic process is performed to the glasssubstrate G.

Thereafter, the glass substrate G is conveyed into the second coolingdevice 16, a cooling process according to the same steps as thosedescribed in FIGS. 8 to 11. In the cooling process in the cooling device16, the glass substrate G is directly placed on the placing surface ofthe placing table 21 as described above. The temperature distribution ofthe glass substrate G cooled by the cooling device 16 is more uniformthan that of the glass substrate G cooled by the cooling device 14. Thisis because, when the temperature distribution is not uniform in thecoating step serving as the next step, a coating film having a uniformthickness cannot be formed. In the cooling device 14 described above,the contact members 26 are used to suppress contamination adhering tothe placing table 21 from adhering to the glass substrate G, and thecooling process is performed. However, in the cooling device 16 used inthe cooling step before the coating step, in order to making uniformityof the temperature distribution good, the glass substrate G is directlyplaced on the placing surface of the placing table 21.

In order to suppress the contamination of the placing table 21 of thesecond cooling device 16 from adhering to the glass substrate G, an air,N₂ gas, or the like is sprayed on the placing surface of the placingtable before the glass substrate G is placed on the placing table 21, ameans for removing contamination is preferably arranged.

After the temperature of the glass substrate G is set at thepredetermined temperature, the glass substrate G is unloaded from thecooling device 16 by the main arm 8 shown in FIG. 1, the glass substrateG is loaded into other devices 11, 12, 13, 15, and 17 shown in FIG. 1according to a predetermined program, and predetermined processes areperformed to the glass substrate G.

The effects of the cooling devices 14 and 16 will be described belowwith reference to FIG. 12 described in the description of the prior art.

In the cooling process of the present invention, as indicated by a curve(b), after the glass substrate is quickly cooled to the temperature K2or less by the first coolant having a temperature kept at thetemperature K2 or less, the temperature of the substrate is adjusted tothe temperature K2 by using the second coolant having a temperature keptat the temperature K2. As a result, unlike the case of the conventionalcooling device indicated by a curve (a), the temperature is notasymptotic to the temperature K2. For this reason, as is apparent fromcomparison between the curves (a) and (b), the cooling time of thesubstrate G can be shortened by a time corresponding to (T3−T2).

As described above, the placing table 21 is cooled by the first coolanthaving a temperature lower than a predetermined temperature, the glasssubstrate G is cooled to the target temperature or less, and the firstcoolant is switched to the second coolant having a temperature almostequal to the predetermined temperature by the electromagnetic valves 32,33, 34, and 35 to supply the second coolant. For this reason, since thetemperature of the glass substrate G can be set at the predeterminedtemperature within a short time, a time required for a large number ofcooling steps in the series of photography steps can be shortened, and athroughput can be considerably increased.

Since the contact members 26 consisting of a material having good heatconductivity are arranged at at least a plurality of positions at equalintervals between the glass substrate G and the placing table 21 of thecooling device 14, the glass substrate G can be uniformly cooled in thecooling steps. Therefore, the contact members 26 can contribute toimprovement of the processing quality of the glass substrate G and anincrease in yield.

When the contact members 26 consist of a good conductive material, e.g.,a metal such as aluminum, the cold of the placing table 21 can beefficiently conducted to the glass substrate G, and the cooling effectfor the glass substrate G can be improved. In contrast to this, when thecontact members 26 consists of an insulating material, e.g., a polyimidefilm, the thickness of the polyimide film is as thin as possible, e.g.,0.1 mm or less. For this reason, heat conduction by radiation andconversion between the placing table 21 and the glass substrate G can bequickly performed, and a time required for the cooling steps isshortened, thereby contributing to an increase in throughput.

In the cooling step before the coating step, the glass substrate G isdirectly placed on the placing table 21. For this reason, uniformity ofthe temperature distribution in the cooling process is improved, and acoating film can be uniformly formed in the coating step following thecooling step. A preferable effect is given to the various processes inthe subsequent steps, e.g., an exposing process, thereby increasing ayield.

Another embodiment different from the cooling devices 14 and 16described above will be described below with reference to FIGS. 13 and14. The same reference numerals as in the cooling device described inFIG. 2 denote the same parts in FIG. 13, and a description thereof willbe omitted.

In a cooling device 80 shown in FIG. 13, a first coolant supply means 30for supplying and circulating a coolant having a temperature kept at atarget temperature for cooling the glass substrate G, e.g., about 18°C., into a coolant path 28 inside a placing table 21, andelectromagnetic valves 32 and 33 serving as a means for opening/closingthe coolant supply means 30 are arranged as a coolant cooling means anda switching means, respectively. The coolant used in this case is, forexample, a cooling liquid or gas described above. In this embodiment, asis apparent from FIG. 13, the second coolant supply means 31 of thedevice in the above embodiment and equipments related to the secondcoolant supply means 31 are not arranged.

In the cooling device, the following processing step is performed. Inthe processing device shown in FIG. 1, as in the device described above,the glass substrate G is unloaded from the carrier 6 through the conveymechanism 7 and the main arm 8, and the glass substrate G iswater-washed with a brush in the device 11, and the glass substrate G isjet-water-washed by a jet water-washing device 12 as needed. Thereafter,the heat-processing unit 13 performs a heating process to the glasssubstrate G at a temperature of about 90° C. or more. The glasssubstrate G is unloaded from the heat-processing unit 13 by the main arm9 and loaded into the cooling device 80 arranged as shown in FIG. 13. Inthe cooling device 80, the glass substrate G is delivered bypre-programmed procedures onto the upper ends of the support pins 23which extend from the upper surface of the placing table 21 and are onstandby. After the main arm 9 delivers the glass substrate G onto thesupport pins 23, the main arm 9 is withdrawn from the cooling device 80.

In the cooling device 80, the following processes are performedaccording to the flow chart shown in FIG. 14. More specifically, in stepS50, the support pins 23 are moved downward, and the glass substrate Gserving as an object to be processed is placed on the placing table 21.The temperature of the placing table 21 is kept at the temperature of anatmosphere in which the cooling device 80 is arranged, i.e., atmospherictemperature, e.g., 23° C. In step S51, the temperature sensors 36intermittently or continuously detect the temperature the placingsurface of the placing table 21. In step S52, the control means 37checks, on the basis of the detected temperature detection signal,whether the temperature of the placing surface is changed by placing thesubstrate G on the placing surface. If NO in step S52, the control means37 determines that the temperature of the glass substrate G isatmospheric temperature to convey the glass substrate G, the controlmeans 37 drives the air cylinder 25 to move the support pins 23 upward,in order to convey the glass substrate G to the next step. On the otherhand, when a change in temperature, e.g., temperature ascending occurs,the cooling process is started in step S53. More specifically, theelectromagnetic valves 32 and 33 are opened in response to a controlsignal from the control means 37 which receives the temperaturedetecting signal to supply a coolant having a temperature kept atatmospheric temperature or less, e.g., 18° C., into the coolant path 28in the placing table 21, and not only the placing table 21 but also theglass substrate G are quickly cooled. In addition, after temperaturedetection is performed in step S54, the control means 37 checks, throughthe temperature sensors 36, whether the temperature of the glasssubstrate G becomes lower than a predetermined temperature, e.g., 23°C., (step S55). If NO in step S55, the control means 37 determines thatthe cooling process-is not sufficiently performed, and the coolingprocess is continued until the temperature becomes lower than 23° C.,i.e., the coolant continuously flows into the cooling path. On the otherhand, when the control means 37 detects that the temperature of theplacing table 21 becomes lower than 23° C., the control means 37transmits a control signal to the switching means 32 and 33 the momentthe temperature becomes lower than 23° C. or a predetermined after thetemperature becomes lower than 23° C. to stop the supply of the coolant(S57). Simultaneously with step S56 or before or after step S56, thecontrol means 37 transmits a control signal for upward driving to theair cylinder 25 in step S56, and the support pins 23 moved upwardaccordingly separates the glass substrate G from the placing table 21.In this state, when the glass substrate G is exposed in aroom-temperature atmosphere for a predetermined time, the temperature ofthe glass substrate G is set at a predetermined temperature, e.g., 23°C. Since the time for this step is properly set as temperature changecharacteristics by the side of the glass substrate, time, the intervalbetween the glass substrate and the upper surface of the placing table,when such information is input to the control means in advance, theoptimum time can be automatically set. When the control means 37determines, on the basis of the temperature change characteristicinformation, that the temperature of the glass substrate G becomes 23°C., the glass substrate G is unloaded at a predetermined timing from thecooling device 14 by the main arms 8 and 9 serving as a convey means.Thereafter, the support pins 23 are kept at the upper position to be onstandby for the next glass substrate which is to be conveyed. Therefore,when the substrate G is cooled to 23° C. or less and then exposed in a23° C. atmosphere, quick temperature control can be performed, and athroughput can be increased.

In the cooling device 80 described in FIG. 13, as described in FIG. 9,the coolant is supplied into the coolant path 28 the moment thetemperature of the placing table 21 is changed by loading the glasssubstrate G onto the placing table 21 or a predetermined time after thetemperature of the placing table 21 is changed, otherwise, as in thecase described with reference to FIG. 10, the coolant may be suppliedinto the coolant path 28 the moment the glass substrate G is loaded ontothe placing table 21 or a predetermined time after the glass substrate Gis loaded onto the placing table 21. In addition, as in the casedescribed with reference to FIG. 11, the coolant may be supplied intothe coolant path 28 the moment the support pins 23 are moved downward ora predetermined after the support pins 23 are moved downward. After theglass substrate G is cooled to a predetermined temperature or less asdescribed above, the glass substrate G is exposed in an atmosphere of apredetermined temperature, thereby setting the temperature of the glasssubstrate G at a predetermined temperature.

In either of the above embodiments, although the glass substrate isexemplified as a substrate to be processed, the substrate is not limitedto the glass substrate, other substrates such as a semiconductor wafer,a printed board, a glass mask, and the like may be used. In order topeel the glass substrate G from the placing table 21, when an N₂ gas issupplied between the glass substrate G and the placing table 21 toeliminate a residual pressure, the glass substrate G can be easilypeeled from the placing table 21. In this case, the N₂ gas may besupplied onto the upper surface of the placing table 21 through thethrough holes 22, formed in the placing table 21, for vertically movingthe support pins 23. When ions formed by an ionizer are mixed with theN₂ gas, static electricity generated by peeling the glass substrate Gfrom the placing table 21 can be prevented. Furthermore, in order tocool the glass substrate G placed on the placing table 21, an invertertype cooling device or a non-inverter type cooling device may also beused. In this case, an auxiliary heater is effectively used to controlthe cooling temperature at a high accuracy. A method in which a cooleris brought into contact with or close to the placing table 21 to performa quick cooling operation may also be used. When the cooler is close tothe placing table 21, the cooling temperature or cooling speed can becontrolled by adjusting the distance between the cooler and the placingtable 21.

As in the first cooling device, when a thin-plate-like object to beprocessed such as a glass substrate is placed on the contact members 26to cool the object, the object is easily bent, and the interval betweenthe upper surface of the placing table 21 and the lower surface of theobject is made ununiform. For this reason, ununiform cooling may beperformed, or the object may not be cooled to a desired temperature.Therefore, in consideration of bending of the object, a curved recessedportion corresponding to the bending may be formed between the contactmembers on the upper surface of the placing table 21. When the object isbrought into direct contact with the upper surface of the placing tableas in the second cooling device, the pressure between the object and theupper surface of the mounting table is made negative to enhance thedegree of contact between the object and the placing table, therebymaking it possible to perform uniform temperature control.

In either of the above embodiments, although the coolant having atemperature lower than the target temperature is used as a cooling meansfor cooling an object to be processed to the target temperature or less,a cooling means using another physical phenomenon, e.g., an electricalmeans such as a Peltier element, may be used such that the electricalmeans is arranged on the placing table. In addition, when thetemperatures of not only the placing table but also the object aremeasured, the cooling means is ON/OFF-controlled by the control means37, and a switching operation between the cooling means and a heatingmeans for heating the cooled object to a temperature almost equal to thetarget temperature is performed by the control means 37. However,without measuring the temperature, and all or some of the operationtimings may be controlled by preformed monitor data through a controlmeans. For example, the relationships among the temperature of theobject to be cooled, the start time of the cooling means, and time atwhich the cooling means is switched to the second cooling means arecalculated by experiment, and the resultant data is input to the controlmeans in advance. The cooling means and/or the heating means may becontrolled on the basis of the stored information.

In the above embodiments, the temperature detecting means is provided inthe placing table; however, it may be provided near the top end of thesupport pin or pins 23 or at the main arm by which the glass substrateis carried to the support pins. The temperature of the glass substratecan thus be measured directly. Furthermore, the glass substrate beingcarried to the support pins by the main arm can be precooled by blowingcooling gas such as N₂ gas thereonto. The temperature of the precoolingcan be set to any value between the initial heating temperature andtarget temperature and determined by both the carrying time of the glasssubstrate using the main arm and the blowing temperature of the coolinggas.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details, representative devices, andillustrated examples shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

1. A cooling method for cooling a substrate loaded on a placing table bysupplying a coolant having a temperature lower than a target temperatureinto a coolant path arranged in said placing table, comprising: loadingthe substrate on the placing table while setting in advance thetemperature of the placing table at a temperature substantially equal tothe target temperature; starting the supply of the coolant in thecoolant path when the temperature of the placing table changes or apredetermined time passes after the temperature of the placing tablechanged, thereby cooling the placing table together with the substrate;and unloading the substrate from the placing table after the temperatureof the placing table is rendered equal to or lower than the targettemperature, and heating the substrate to the target temperature in anatmosphere having a temperature substantially equal to the targettemperature.
 2. A cooling method for cooling a substrate loaded on aplacing table by supplying a coolant having a temperature lower than atarget temperature into a coolant path arranged in said placing table,comprising: loading the substrate on the placing table while setting inadvance the temperature of the placing table at a temperaturesubstantially equal to the target temperature; starting the supply ofthe coolant in the coolant path when the substrate is loaded on theplacing table or when a predetermined time passes after the substratewas loaded on the placing table, thereby cooling the placing tabletogether with the substrate; and unloading the substrate from theplacing table after the temperature of the placing table is renderedequal to or lower than the target temperature, and heating the substrateto the target temperature in an atmosphere having a temperaturesubstantially equal to the target temperature.
 3. A cooling method forcooling a substrate loaded on a placing table by supplying a coolanthaving a temperature lower than a target temperature into a coolant patharranged in said placing table, comprising: loading the substrate on theplacing table while setting in advance the temperature of the placingtable at a temperature substantially equal to the target temperature;starting the supply of the coolant in the coolant path when, after thesubstrate is received by means of a plurality of support pins above theplacing table, and the support pins are descended, or when apredetermined time passes after the support pins are descended, therebycooling the placing table together with the substrate; and unloading thesubstrate from the placing table after the temperature of the placingtable is rendered equal to or lower than the target temperature, andheating the substrate to the target temperature in an atmosphere havinga temperature substantially equal to the target temperature.